Two days after the second drowning in Lake Pontchartrain in six weeks, the University of New Orleans has closed off public access to Pontchartrain Beach until further notice. That decision, which was made Tuesday night, applies to a strip of lakefront property behind UNO's Research and Technology Park, UNO spokesman Mike Rivault said.

Michael DeMocker / The Times-PicayuneMembers of New Orleans EMS, the fire and police departments carry the victim from the shoreline as they try to save a young man was underwater for several minutes before being pulled from the water at Pontchartrain Beach on Monday, May 14, 2012.

Two gates, one at each end of the tract, have been closed and locked, he said, and "No Trespassing" signs will be posted. UNO police have started monitoring the area, and violators will be escorted off the property.

The beach has been popular even with nonswimmers.

UNO's lease for the property requires public access to it, but Rivault said the lease does allow closure when public safety is involved.

In addition to stepped-up patrolling, Rivault said, UNO might erect more signs, as well as a fence that would let people use the beach but not venture into the water.

The Coast Guard has increased its patrolling of the lake and other waterways, but that is governed more by the time of year, when more people go outside, than by the drownings, Petty Officer Stephen Lehmann said.

"We keep our eyes on the shore," he said, "and we advise boaters about the importance of life jackets."

The latest drowning occurred Monday, when Shone Badon, 17, didn't resurface after swimming with two women. He was pulled from the water after a few minutes, and he died that night.

Bindar Lopez, 17, dived into the lake from a pier last month while on an outing with his family. He didn't resurface. His body was found two days later.

Swimming in the lake already had been prohibited when the recent drownings occurred and signs bearing that message were visible.

Nevertheless, Rivault said, "people are attracted to water."

There was no indication on Wednesday how long the ban will last.

"We don't want to make it longer than it has to be," Rivault said.

A friend of the teenager who drowned this week said the lake floor where he was swimming is marked by sudden, treacherous dropoffs.

In that area are blocks of concrete, called groins, that are risky because they can be slippery from algae buildups, said John Lopez, executive director of the Lake Pontchartrain Basin Foundation.Also, he said, depressions in the lake bottom are deeper near these structures because the wave action interacts with the rocks in the lake.

From a biochemical standpoint, the lake has been safe for swimming for several years, Lopez said, although it probably isn't wise to swim for two or three days after a heavy rainfall because large amounts of potentially contaminated storm water is pumped into the lake.

Despite his views on swimming in the lake, Lopez took pains to point out that he didn't want to accuse UNO of overreacting.

"We respect UNO in terms of its position and influence," he said. "We're hoping to explore what needs to be done."

For about 10 years, the foundation has conducted swimming classes for children.

But, Lopez said, knowing how to swim doesn't immunize one from the possibility of drowning.